The present invention pertains to display of signals and pertains particularly to a waveform zoom feature within an instrument having a table driven graphical display.
Signal analysis systems, such as optical spectrum analyzers, multi-wavelength meters and oscilloscopes, generally allow display of one or more waveforms, each waveform representing a signal or signal portion. Some signal analysis systems allow both a tabular display and a graphical display of multiple waveforms.
It is often desirable to zoom in on particularly areas of interest in a single waveform within a graphical display of multiple waveforms. For example, within a spectral analysis system, to graphically view the center wavelength of a particular waveform of interest, a user first manually enters the center wavelength. The center wavelength can be obtained, for example, from a value listed in a tabular display. The user can then manually adjust the graph wavelength span until the desired view is achieved.
Alternatively, to graphically view the center wavelength of a particular waveform of interest, a marker search function can be used to position a marker on the signal of interest. If available, the user can then utilize a xe2x80x9cMarker- greater than Centerxe2x80x9d function. After the xe2x80x9cMarker- greater than Centerxe2x80x9d function is used, the user can manually adjust the graph wavelength span until the desired view is achieved.
The above-described methods to graphically view the center wavelength of a particular waveform of interest both require the user to perform several manual adjustments in order to achieve the desired graphical view of the desired waveform. In order to restore the original multi-waveform view, the user then has to perform several more manual adjustments.
The situation is the same for other types of instruments that provide both a graphical view of a raw measurement trace along with some number of numerical parameters derived from the raw measurement trace. If the user is interested in zooming in on just the portion of the trace used to calculate a particular numerical parameter, the graphical limits must be adjusted manually.
In accordance with the preferred embodiment of the present invention, a display for an instrument includes a graphical display and a tabular display. On the graphical display is shown a plurality of traces. The tabular display lists, for each of at least a portion of the traces, a center point of interest to a user. Upon the user selecting a first center point for a first trace, the graphical display shows just the first trace. A horizontal span of the graphical display is adjusted to equal a preselected zoom span.